In the medical field, implantable leads are used with a wide variety of medical devices. For example, implantable leads are commonly used to form part of implantable cardiac pacemaker systems that provide therapeutic stimulation to the heart by delivering pacing, cardioversion or defibrillation pulses. The pulses can be delivered to the heart via electrodes disposed on the leads, e.g., typically near distal ends of the leads. In that case, the leads can position the electrodes with respect to various cardiac locations so that the pacemaker can deliver pulses to the appropriate locations. Leads are also used for sensing purposes, or both sensing and stimulation purposes.
In addition, implantable leads are used with neurological devices such as deep-brain stimulation devices, and spinal cord stimulation devices. For example, leads can be stereotactically probed into the brain to position electrodes for deep brain stimulation. Leads are also used with a wide variety of other medical devices including, for example, devices that provide muscular stimulation therapy, devices that sense chemical conditions in a patient's blood, gastric system stimulators, implantable nerve stimulators, implantable lower colon stimulators, e.g., in graciloplasty applications, implantable drug or beneficial agent dispensers or pumps, implantable cardiac signal loops or other types of recorders or monitors, implantable gene therapy delivery devices, implantable incontinence prevention or monitoring devices, implantable insulin pumps or monitoring devices, implantable hearing restoration devices, and the like. In short, medical leads can be used for sensing purposes, stimulation purposes, drug delivery, and the like.
A number of challenges exist with respect to medical leads. In particular, new and improved lead designs are often needed to facilitate medical implantation to specific locations within a patient. For example, as more advanced and complex pacing techniques are developed, it becomes desirable to facilitate lead implantation at new cardiac locations. Some recent advancements in pacing have made use of non-conventional locations for delivery of pacing pulses, such as left ventricular locations, atrial roof locations and epicardium locations to name a few. Other non-conventional locations for delivery of therapeutic pulses to the heart or other body locations will likely be discovered and used in the future.